"The environmental concerns are very legitimate," he told reporters in Brisbane.

The admission was made as the Queensland government put two Chinese property groups and gaming giants Crown Resorts and Echo Entertainment on the short list to develop Brisbane's second casino.

Hong Kong-based Far East Consortium/Chow Tai Fook Enterprises and Shanghai-based Greenland Investment, a state-owned corporation, are also in the running.

Mr Seeney became defensive when asked about why Queensland, which has four of Australia's 13 casinos, needed three new gaming houses in cities that already have a casino.

"I've made that point a dozen times since this process started and I will continue to make it," he said.

"They are not, and I repeat, they are not stand-alone casinos of the like which you are familiar with."

Mr Seeney said Brisbane's second casino, catering to international high rollers, could be better than Sydney's second casino at Barangaroo, a Crown development due to open in November 2019.

It would also be near the historic Treasury casino, which owner Echo Entertainment has previously hinted could be converted into a boutique restaurant complex if it gets Brisbane's second casino licence.

With a Brisbane development decision due early next year, Mr Seeney said all short-listed bids would be "absolutely" knocked back if they failed on probity and casino licensing grounds.

"Unless the proponents can meet both of those issues, then they won't proceed," he said.